1. Field of the Invention
The present invention relates to a width measuring method using a surface texture measuring instrument. More specifically, it relates to a width-measuring method for measuring a width of a workpiece with a surface texture measuring instrument having a detector capable of changing measuring attitude thereof.
2. Description of Related Art
Many of detectors used in a surface texture measuring instrument such as roundness measuring instrument, surface roughness measuring instrument and contour measuring instrument are provided with a contact piece attached to a tip end of a lever pivotably moved in a direction orthogonal to a surface of a workpiece, the detectors scanning the surface of the workpiece while keeping the contact piece in contact with the workpiece surface to collect measurement data, thereby analyzing the surface texture of the workpiece and/or measuring coordinates and dimension of the workpiece.
However, since the detectors of this type are single-axis detectors that detect irregularities in pivoting direction (i.e. Z-axis (vertical) direction in a surface roughness measuring instrument and contour measuring instrument and X-axis (front and back) direction in a roundness measuring instrument), though irregularities in the pivoting direction can be highly accurately detected, the data of a workpiece surface orthogonal to the pivoting direction (i.e. along the workpiece surface) is difficult to be collected. For instance, characteristic-shape point such as workpiece edge (such edge is usually angled by ninety degrees) has been difficult to be directly detected and, especially, the width of recesses and treads of grooves and the like formed on the workpiece surface has been difficult to be accurately measured (for instance, see Japanese Patent Laid-Open Publication No. 2001-343228).
Further, since the attitude and scanning direction of the detectors relative to the workpiece are restricted, accurate scanning often cannot be conducted on a desired location of workpiece surface.
Furthermore, since the measurable area is restricted on account of interference between the components of the detector and the workpiece, desired position of the workpiece often cannot be measured.
As a result, in order to accurately measure a workpiece, in addition to the measurement of the contour and roundness of the workpiece by the surface texture measuring instrument, the workpiece has to be set on another dedicated measuring instrument to measure the width and diameter of the workpiece, which increased the measurement steps and time, thereby deteriorating the efficiency of the entire measurement of the workpiece.
In order to solve the above-described disadvantages, an object of the present invention is to provide a surface texture measuring instrument capable of overcoming the restriction on the scanning direction and measurable area of the detector relative to a workpiece and width-measuring method using the surface texture measuring instrument.